Patent Application
20230193009
The invention relates to a process for the manufacture of hybrid products comprising at least two different elastomer materials bonded to each other, said at least two different elastomer materials being based on at least one rubber of the ethylene propylene diene monomer (EPDM) type and at least one rubber of the silicone type. The inventive process is particularly useful for the manufacture of EPDM-silicone hybrid sealing profiles.
Ethylene-propylene-diene (EPDM) and silicone polymer materials have advantages and disadvantages.
EPDM has good weather resistance (ozone, UV, temperature) and physical/mechanical properties (tearing resistance, compression set, elongation), and its processability allows complicated shapes. Also, it has a good price-performance ratio. Its disadvantages are that the range of possible colors is limited. While black is easy to produce, other colors are difficult to produce. The carbon black used to produce black EPDM is responsible for some of the good physical properties, but replacing carbon black in colored compounds reduces the physical properties of EPDM. Due to the high viscosity of the EPDM compounds wall thicknesses below 0.8 mm are difficult to extrude. Also, the price of colored EPDM materials is much higher than for black EPDM.
Silicone has excellent weather resistance (ozone, UV, temperature) and physical/mechanical properties. The compression set is even better than for EPDM, and the mechanical properties do not change over a wide temperature range. Also, there are no limitations in colors, even transparent is possible, and silicone has good compatibility to structural glazing facade application. The disadvantages of silicone are the relatively low tearing resistance, the bad compound availability, and the high price.
It has long been attempted to make composite materials that combine in the same product the qualities inherent in each of the rubbers of the silicone type and the ethylene-propylene copolymer or terpolymer type. U.S. Pat. No. 5,346,760 describes a two-layer composite material based on such rubbers. The layers, however, have a complex composition. The first layer comprises a silicone rubber and an ethylene-propylene copolymer and/or terpolymer rubber. The second layer comprises an ethylene-propylene copolymer and/or terpolymer and a different rubber such as nitrile rubber, styrene-butadiene rubber or natural rubber. Also, both layers need to contain a specified amount of silica with a specified pore volume and average particle size.
It is an object of the invention to provide a process for bonding EPDM rubber material to silicone rubber material to thus allow the manufacture of EPDM-silicone hybrid products that combine the advantages of both EPDM and silicone materials and eliminate the disadvantages of the single materials.
Any references to singular characteristics or limitations of this specification shall include the corresponding plural characteristic or limitation, and vice versa unless otherwise specified or clearly implied to the contrary by the context in which the reference is made. All references to one (including the articles “a” and “the”), two or another number of objects are, provided nothing else is expressly mentioned, meant to be understood as not excluding the presence of further such objects in the invention.
All the embodiments of the invention described herein are contemplated from and may be read from both an open-ended and inclusive view (i.e., using “comprising” language) and a closed and exclusive view (i.e., using “consisting of” language). The term “comprising” thus encompasses and includes the more restrictive terms “consisting essentially of” and “consisting of”.
As used herein parentheses are used to designate that something is optionally present, to qualify or further define a previously mentioned term, or to list narrower embodiments.
Except where otherwise indicated, all numerical quantities in the following detailed description (e.g., amounts, ranges, ratios, reaction conditions, or the number of atoms in a chemical formula) are to be understood as modified by the word “about”.
The term “about” can indicate a variation of 10% of the value specified, e.g., about 50% carries a variation from 45 to 55%. For integer ranges, the term “about” can include one or two integers greater than and less than a recited integer.
Unless otherwise indicated, all percent values regarding amounts, ranges, and ratios are based on the weight.
It is to be understood that upper and lower amounts, ranges, and ratios set forth herein may be independently combined. Similarly, the amounts, ranges, and ratios for each element of the invention can be used together with amounts, ranges, and ratios for any of the other elements.
Unless otherwise indicated, each chemical or composition referred to herein should be interpreted as being a commercial grade material which may contain the isomers, by-products, derivatives, and other such materials which are normally understood to be present in the commercial grade.
Any reference numerals in the patent claims are not meant to be limiting but merely serve to improve the readability of the claims.
According to the invention, the above problem is solved by a process for the manufacture of hybrid products comprising at least two different elastomer materials bonded to each other, said at least two different elastomer materials being based on at least one rubber of the ethylene-propylene-diene (EPDM) type and at least one rubber of the silicone type;
R3Si—[O—SiR2]n—O—SiR3;
The inventive process surprisingly allows the manufacture of EPDM-silicone hybrid products. The EPDM-silicone hybrid products obtained have excellent weather resistance (ozone, UV, temperature) and physical/mechanical properties (in particular tearing resistance, compression set, elongation) which do not change over a wide temperature range. There are no limitations in colors, even transparent is possible. The processability of the material allows complicated shapes (e.g., profiles), and the material has good compatibility to structural glazing facade application. Also, the price-performance ratio is very good.
The inventive process is particularly useful for the manufacture of EPDM-silicone hybrid sealing profiles, e.g., for window frames or door frames. An advantage is that in comparison to full silicone profiles the manufacturing costs are significantly reduced.
The silicone rubber used in the inventive process comprises alkenyl functionalized polydialkylsiloxanes of the general formula:
R3Si—[O—SiR2]n—O—SiR3;
Suitable C1-C8 alkyl groups may have straight or branched chains and may be unsubstituted as well as substituted. In one embodiment of the inventive process, the used alkenyl functionalized polydialkylsiloxane comprises C1-C6 or C1-C4 alkyl groups.
Specific examples for alkyl groups are methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, tert.-butyl, n-pentyl, iso-pentyl, n-hexyl, iso-hexyl, n-heptyl, iso-heptyl, n-octyl or iso-octyl groups. The skilled artisan appreciates that for higher alkyl groups the term “iso” comprises more than one possible isomer. All possible isomers of the above alkyl groups are suitable in the inventive process.
Suitable C1-C8 alkenyl groups may have straight or branched chains and may be unsubstituted as well as substituted. Higher alkenyl groups may contain more than one double bond which may be conjugated or not. In one embodiment of the inventive process. the used alkenyl functionalized polydialkylsiloxane comprises C1-C6 or C1-C4 alkenyl groups.
Specific examples for alkenyl groups are ethenyl (vinyl), n-propenyl, iso-propenyl, n-butenyl, iso-butenyl, tert.-butenyl, n-pentenyl, iso-pentenyl, n-hexenyl, iso-hexenyl, n-heptenyl, iso-heptenyl, n-octenyl or iso-octenyl groups. The skilled artisan appreciates that for higher alkenyl groups the term “iso” comprises more than one possible isomer. All possible isomers of the above alkenyl groups are suitable in the inventive process.
The degree of alkenyl functionalization (the content of alkenyl groups) of the polydialkylsiloxanes used in the inventive process is not subject to any special restrictions or limitations and may be selected by the skilled person according to practical circumstances or as desired. The content of alkenyl groups may be, for example, 0.01 to 10 mol %, especially 0.1 to 1 mol % of the entire R groups.
The natural number n specifying the number of repeating units in the used alkylene functionalized polydialkylsiloxane is not subject to any special restrictions or limitations and may be selected by the skilled person according to practical circumstances or as desired. For example, n may be selected so that the used alkylene functionalized polydialkylsiloxane has a suitable viscosity for extrusion.
In one embodiment of the invention, the used alkenyl functionalized polydialkylsiloxan is a vinyl functionalized polydimethylsiloxane. A suitable vinyl functionalized polydimethylsiloxane is, e.g., commercially available under the trade name ELASTOSIL® R 401/70 S.
The EPDM rubbers used in the inventive process are not subject to any special restrictions or limitations and may be selected by the skilled person according to practical circumstances or as desired. The diene component of the EPDM rubber may be a conjugated or non-conjugated diene. Exemplary of dienes employed in the EPDM are 5-methylene-2-norbornene, 5-ethylidene-2-norbornene, cyclooctadiene, 2-methyl-1,4-pentadiene, 1,4-hexadiene, 4-methyl-1,4-hexadiene, 1,4-heptadiene, 4-methyl-1,4-heptadiene, 4-ethyl-1,4-heptadiene, 1,5-heptadiene, 1,5-octadiene, 5-methyl-1,5-heptadiene, 2-methyl-1,5-hexadiene, 1,6-octadiene, 6-methyl-1,6-octadiene, 2-methyl-1,6-heptadiene, 1,9-decadiene, 1,13-tetradecadiene, vinylcyclohexene, vinylnorbornene, dicyclopentadiene, 1,3,7-octatriene, and 1,5,9-decatriene. These diene compounds may be used alone or in admixture of two or more.
The peroxide curing agent used in the inventive process is not subject to any special restrictions or limitations and may be selected by the skilled person according to practical circumstances or as desired. Examples for suitable peroxides are acetyl peroxide, benzoyl peroxide, lauroyl peroxide, bis-(2,4-dichlorobenzoyl)peroxide, dicumyl peroxide, tert-butyl peroxyperbenzoate, tert-butyl peroxypivalate, di-tert-butyl peroxide, 2,5-bis-(tert-butylperoxy)-2,5-dimethylhexane, and bis(tert-butyl peroxy isopropyl)benzene. The peroxide curing agent may be used, for example, in an amount of about 1 to 50 parts by weight per 100 parts by weight of the materials to be polymerized by free radicals. It should be noted that curing could also be performed by radiation if desired.
In one embodiment of the inventive process, when the used alkenyl functionalized polydialkylsiloxan is a vinyl functionalized polydimethylsiloxane (e.g., ELASTOSIL® R 401/70 S, the used curing agent may suitably be bis-(2,4-dichlorobenzoyl)peroxide, dicumyl peroxide, or 2,5-bis-(tert-butylperoxy)-2,5-dimethyl-hexane.
In the invention, the EPDM-silicone hybrid product may be manufactured, for example, directly by coextrusion (multiextrusion) of a curable composition comprising a suitable EPDM compound and a curable composition comprising a suitable alkenyl functionalized polydialkylsiloxane compound on a coextruder (multiextruders), followed by covulcanization (multivulcanization). The coextrusion(multiextrusion) may be performed, for example, at a temperature in the range of from 40 to 250° C., such as 100 to 250° C. or 100 to 200° C., preferably in the range of from 40 to 70° C., and, for example, for a period of from 3 minutes to 3 hours. Optionally, a pressure ranging, for example, from 2 to 50 MPa, preferably 30 to 50 MPa, may be applied during extrusion. The covulcanization (multivulcanization) is performed in the vulcanization zone of the extruder line (e.g., using a salt bath, hot air, ultra-high frequency (UHF) or infrared radiation) and may be performed, for example, at a temperature in the range of from 180 to 270° C. The covulcanization (multivulcanization) may be conducted, for example, for a period of from 30 seconds to 30 minutes.
In one embodiment of the invention 3, to 4, or even more different elastomer materials are used.
In another embodiment of the invention two different EPDM rubber materials and one silicone rubber material are used. In another embodiment of the inventive process one EPDM rubber material and two silicone rubber materials are used.
The skilled person appreciates that the invention is not limited to coextrusion, but that also triple-extrusion or quattro-extrusion (multiextrusion) may be used if suitable or desired.
In one embodiment of the inventive process, since EPDMs cures fast and silicones cure slowly, the curing speed of the EPDM compound and the silicone compound are advantageously adapted to each other. Methods for the adaptation of different curing speeds are known in the art and may involve, for example, the use of different curing agents or different curing agent concentrations.
In another embodiment of the inventive process, the flow speed of the EPDM compound and the silicone compound in the extruder are advantageously adapted to each other so that the compounds have a similar flow speed in the contact areas. Methods for the adaptation of flow speeds in an extruder are known in the art.
In yet another embodiment of the invention, the curing speeds and the flow speeds of the EPDM compound and the silicone compound are advantageously adapted to each other.
In yet another embodiment of the invention, postcuring of the silicone layer is conducted, preferably for 3 to 24 hours, e.g., 3 hours.
The skilled person appreciates that the used curable composition comprising a suitable EPDM compound and/or the curable composition comprising a suitable alkenyl functionalized polydialkylsiloxane compound may optionally contain various known additives such as reinforcing or extending fillers, plasticizers, lubricating agents, blowing agents, antioxidants, anti-UV additives, colorants, and pigments. Specific examples for additives are ground quartz, calcinated clays, calcium carbonate, zinc oxide, iron oxide, titanium oxide, cobalt oxide, magnesium oxide, aluminium oxide, carbon black, magnesium and aluminium silicates, aluminium, calcium and barium sulfates, asbestos, glass and carbon fibers, synthetic fibers such as aramid, polyester, polyamide and rayon. Various known mixing methods are possible for incorporating the above additives into the curable compositions, the order of introduction of the various constituents not being critical.
In one embodiment of the invention the silicone rubber is present on the surface of the hybrid product. The thickness of the applied silicone rubber may be variable. The lowest thickness may be, for example, 2 mm to 0.01 mm or 0.5 mm to 0.05 mm.
In a further preferred embodiment of the invention a layer of silicone is extruded on the EPDM part also around the foot of a EPDM-silicone hybrid profile. Preferably it is a thin layer having a thickness of 2 mm to 0.01 mm, more preferably 0.5 mm to 0.05 mm.
This means that when the profile is mounted in the groove on a window frame, or door frame etc. the silicone layer is locked inside of the groove. Also coating around the whole profile is possible. An advantage of this is that dyeing of the profile is possible with colors that cannot be used with EPDM, e.g., for making a gold colored profile.
While certain representative embodiments and details have been shown for the purpose of illustrating the present invention, it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the scope of the present invention.
The sealing section 14 consists of a first elastomer material 11 being silicone having a length 102 of 5.5±0.7 cm.
The foot 15 consists of a second elastomer material 12 being EPDM and comprises a bridge 17 and a hook or a groove 16. The bridge 17 has a length 103 of 1.6±0.15 cm. The foot 15 comprises a core 18 inside the foot 15 having a length 104 of 2.4 cm. The foot 15 further provides a recess for a cord 13.
The sealing section 14 is coupled to the groove 15 at a joining section 19 which provides a positive locking, non-positive locking and/or a bonded joint.
A thin layer of the second elastomer material 52, the third elastomer material 53 and the fifth elastomer material 56 is extruded on the forth elastomer material 55.
10 EPDM-silicone hybrid sealing profile
11 first elastomer material
12 second elastomer material
13 cord
14 sealing section
15 groove
16 hook
17 bridge
18 core
19 joining section
101 thickness of first elastomer material
102 length of sealing section
103 length of bridge
104 length of core
20 EPDM-silicone hybrid sealing profile
21 first elastomer material
22 second elastomer material
30 EPDM-silicone hybrid sealing profile
31 first elastomer material
32 second elastomer material
33 third elastomer material
34 cord
40 EPDM-silicone hybrid sealing profile
41 first elastomer material
42 second elastomer material
50 EPDM-silicone hybrid sealing profile
51 first elastomer material
52 second elastomer material
53 third elastomer material
54 forth elastomer material
55 fifth elastomer material
56 sixth elastomer material
60 coextruder
61 first coextruder
62 second coextruder
65 die
66 EPDM-silicone hybrid sealing profile
70 triple-extruder
71 first coextruder
72 second coextruder
73 third coextruder
75 die
76 EPDM-silicone hybrid sealing profile
80 quattro-extruder
81 first coextruder
82 second coextruder
83 third coextruder
84 forth coextruder
85 die
86 EPDM-silicone hybrid sealing profile
| Number | Date | Country | Kind |
|---|---|---|---|
| 19204473.3 | Oct 2019 | EP | regional |
| 20169542.6 | Apr 2020 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2020/079703 | 10/22/2020 | WO |
